This invention relates to digital televisions.
Digital televisions include an antenna, a tuner, a demodulator and a decoder coupled to a display. Because of the nature of a digital television system, a delay is involved in displaying a newly selected channel. Firstly, this is in part due to the fact that digital television tuners lock on new channels more slowly than analog tuners. Secondly, a demodulator may contain an equalizer which does not exist in analog television receivers. These equalizers take time to converge. Thirdly, program stream information is read in order to extract different program elements, such as video and audio, from the broadcast stream to the respective decoders. This is known as demultiplexing.
The video decoding of the demultiplexed signal is the source of still additional delay. A Moving Pictures Experts Group (MPEG) decoder waits for picture parameters such as a valid Intra-coded frame (I-frame), Group of Pictures (GOP) information, and certain buffer fullness indications before it may begin decoding. As a result of all these factors, channel changing may be delayed.
Thus, there is a need for a way to allow digital televisions to switch channels more quickly.